Multilevel resistive switching with ionic and metallic filaments

Abstract

The resistive random access memory (ReRAM) device with three distinguishable resistance states is fabricated by doping Cu into a portion of the ${\text{ZrO}}_2$ oxide layer of the $\text{Ti}/{\text{ZrO}}_2/n^{+}\text{-}\text{Si}$ structure. The temperature-dependent measurement results demonstrate that filaments due to ionic trap-controlled space charge limited current conduction and metallic bridge are formed at different voltages. The formation and rupture of these different conducting filamentary paths in parallel are suggested to be responsible for the multilevel switching with the large resistance ratio, which can be used to establish a reliable multilevel ReRAM solution with variation tolerance.